1. Field
The invention is in the field of cylindrical couplings for joining pipes, hoses, valves, pipe and hose fittings, dead ends, and lids for pressure vessels end-to-end wherein the end portions to be joined include flanges and the coupling holds a gasket for forming a seal.
2. State of the Art
As used herein, including the claims, the word pipe includes not only lengths of pipe, but also valves, hoses, and pipe and hose fittings where a connection is made to a pipe or other hoses or fittings.
In making a conventional vertical radial flange connection of two pipes, two flanges having a series of holes in a bolt circle are mounted on the end portions of the two pipes to be joined, either by welded or threaded joints. The flanges are connected together by bolts while compressing a seal placed between them. Unlike vertical radial flanges, there are also VIC-RINGS produced by Victaulic Company of America, Easton, Pa., U.S.A., over which a gasket is mounted to seal the pipe, and the coupling is made of two arcuate halves. The two ends of the halves are keyed against opposite shoulders and are held together around the gasket by means of bolts passed through two pads. There is also a mechanical coupling known as the DEPEND-O-LOCK coupling produced by Brico Industries Inc., Atlanta, Ga., U.S.A. which coupling is a split sleeve mounted on the end portions of the two pipes to be joined against two key shoulders constructed by welding two rings around the two pipes. The split ends of the sleeve are held together by means of two linear flanges and the bolts. In the above mentioned couplings, in each case a gasket is held in place by the mechanical pressure of the bolts. In the case of the Victaulic and Brico couplings cited above, gaskets are seated around the end portions of the two pipes being connected. The Victaulic Company of America and Brico Industries Inc. both recommend seven steps to install their couplings, where five of the seven steps are common to both of the couplings. These common steps are:                1. Lubricating of the gasket, the end portion of the two pipes, and the interior of the coupling.        2. Aligning the ends of both pipes.        3. Spacing the pipes properly to mount the couplings.        4. Positioning the coupling housing over the gasket to assure the housing keys properly engage the shoulders.        5. Inserting bolts through the flanges and tightening the bolts evenly.        
The current inventor holds the following patents on cylindrical couplings U.S. Pat. Nos. 5,387,017; 5,868,441; 5,794,988 and 6,186,560. This invention provides improved means for the preparation of the end portion of pipes and said means to accommodate a sealing gasket between the pipe ends, which gasket is premounted with a snug fit inside the cylindrical coupling. This is also an improvement over the design in FIGS. 11 and 12 of U.S. Pat. No. 5,868,441, and FIG. 17 of U.S. Pat. No. 6,186,560, where the vertical radial flange (shoulder) is integral or is an inserted end portion of the shank or pipe or hose; the flange is not inclined and it is not welded around the pipe with an offset from the end of the pipe to accommodate the gasket.
In the real world, pipe is produced with plus or minus diametrical tolerances, and plus and minus tolerances are also applied to the ovalness of pipe. Between these two types of tolerances (ovalness and diameter) using cylindrical couplings becomes a problem. Therefore cylindrical couplings are not usually used. Cylindrical couplings, however, are less expensive and much easier to install than other couplings such as those described in this Prior Art section. The flange of the invention in combination with a cylindrical coupling and the gasket provide the quickest and most economical means for the cylindrical couplings to connect two pipes. The invention shortens the over-all length of the cylindrical coupling and reduces cost. The invention provides a free footed seal protected in an enclosure from the damaging high velocities of fluid flowing in pipe line. In installing the cylindrical coupling, this invention eliminate or make easier the five steps mentioned above.